Investigating how personality and mood impact perceived pain experience and expression in the domestic dog

Across the human literature many successful attempts have been made to research how individual differences, such as; emotional predisposition, mood and personality both mediate and moderate how people express that they are in pain, cope with painful conditions and the impact painful conditions have on an individual's quality of life. As such, we have an understanding, albeit not full, of the ways in which pain can impact human life on many levels. We also know that individuals higher in positive affect cope better with compromised health. Despite there being pre-existing literature with nonhuman animals looking at both personality and pain independently, little research has attempted to look at the effect of one on the other. As such, it is unclear what impact, if any, emotional predisposition, mood or personality has on pain behaviour and coping in animals. Dogs are one of the most popular animals to be kept as domestic pets worldwide; further to this they play a crucial role in society in many working roles. There are several health conditions that affect dogs across their lifetime which are thought to cause pain, making them an ideal species to look at the impact of personality and mood on pain behaviour. Pain is exceptionally difficult to assess and monitor in animals, and as such further work in this area is needed. This PhD used a mixture of a systematic review, questionnaire data and biomechanical assessments of gait and pain to start to examine whether pain expression is associated with disease severity, or where other factors such as a dog's personality and mood moderates the relationship between disease severity and pain behaviour. In addition, accelerometers were piloted as an alternative to force plate assessment, to provide accurate, objective pain assessment in clinical settings. The findings suggest that as we see in humans, positive affect is a source of resilience in pain and dogs in pain can be differentiated from their healthy counterparts by lower levels of positive affect. Neuroticism also moderates the effects of severity on pain; higher levels of neuroticism are suggestive of higher levels of pain. Using the method employed in this thesis, accelerometers do not appear to be an alternative tool to assess gait changes related to pain. The implications from these findings are discussed in context with human literature on positive psychology to suggest a reconceptualization of how we view pain and its subsequent treatment in animals.